Safety control apparatus for gaseous fuel burners



June 10, 1952 H. J. LONG 2,600,252

SAFETY CONTROL APPARATUS FOR GASEOUS FUEL BURNERS Filed May 27, 1946 Ticljn 6 i I & l v I COIYTROL s m 7 fid 58% 68:55J C mu s INVENTOR HERBERT J. LONG 66 A 6/5 0 JM I SOLEAg/p 774450-05 fiMosr/IT/c fies-044mg ATTORNEY Patented June 10, 1952 SAFETY CONTROL APPARATUS FOR GASEOUS FUEL BURNERS Herbert J. Long, New York, N. Y., assignor, by mesne assignments, to G. E. S. Devices Corp., New York, N. Y., a corporation of New York Application May 27, 1946, Serial No. 672,645

Claims. 1

The present invention relates to safety control apparatus for gaseous fuel burners and is more particularly directed toward automatic pilot control for a main fuel burner such as in a cook stove, oven or furnace.

The present invention aims to provide controls for gaseous fuel burners which make it possible, on opening of a main valve, to supply fuel to a pilot burner and concurrently with the opening of the main valve to connect into a circuit an electric ignition device, such as a resistance coil adjacent the pilot burner whereupon the ignition device immediately lights the pilot. At the same time that the main valve is opened it admits gas to a normally closed solenoid valve which controls the flow of fuel to a main burner.

Within a very short time after the ignition circuit has been energized the pilot burner lights and heats a thermal element, causing it to expand, and the expansion of this thermal element operates a circuit changing device such as a simple switch blade to open the ignition circuit and circuit conditions.

A further object of the present invention is to provide a pilot burner for gaseous fuel burners which employs electrical energy for ignition purposes for only a very short time whereupon the ignition device is disconnected from the circuit so that it has negligible energy consumption and a very much longer operating life than ignition coils continuously in circuit. A further object of the invention is to so arrange the parts that their operation is not aifected in any substantial manner by varying ambient temperatures.

A further object of the invention is to so cate the pilot control parts relative to the main burner that they are protected against injury by heat produced by the main burner.

Other and further objects will hereinafter appear as the description proceeds.

The accompanying drawings show, for purposes of illustrating the present invention, an embodiment in which the invention may take form, it

. ,2 being understood that the drawings are illustrative of the invention rather than limiting the same. 7 Inthese drawings: Figure 1 is a top plan view with parts in section illustrating a gaseous fuel burner with associated safety controls; V j

Figure 2 is a side elevational view of the controlling apparatus taken in the direction ofth arrow 2 of Figure l; I

Figure 3 is a section taken on the line 3-7-3 of Figure2;

Figure 4 is a section taken at an enlarged scale on the line 44 of Figure 1; I v

Figure 5 is a wiring diagram for an oven-control; and v Figure 6 is a schematic illustration of agas fired furnace installation. A conventional gaseous fuel burner is indicated at I0 and the venturi for supplying'the mixture of gas and air at H. The gas is supplied through a normally closed solenoid valve indicated at I2. The solenoid valve receivesgas through a passage [3 from the casing H of a main gas valve having a control spindle indicated at I5 and gas inlet 6. The valve. maybe of the on and off type adapted to be fully open or fully closed, or'may, as shown here; be a variable opening valve, so that variable amounts of fuel may be supplied to the main burner when the solenoid valve permits the flow of fuel. The valve [4 is also connected through a tube l! with a metal block l8 whichin turn is connected through a tube l9 and elbow 20 with a pilot burner 2|. The gas flow is controlled by an adjustable screw 2|. This burner extends adjacent the main burner l0 and has a port'22 for projecting a lighting flame toward the main burner.

The spindle I5 of the main gas valve is here shown as grounded to the stove or furnace-and is adapted, when turned out of the valve'closing position, to engage a contact 25, which will ground a lead 26 from the secondary of a low voltage transformer T, so that whenever the gas valve is opened the transformer secondary is grounded to the burner control. The other side of the transformer is connected by a wire 21 with aterminal 28 insulatedly supported on a bracket 29 carried by the block l8. Lighting circuits may be directly connected without transformer, in which case all conducting parts are insulated from the burner. The terminal 28 carries a downwardly extending contact spring 3o p'ass ing between a cold contact 3| and a ,hot con;

tact 32 and biased toward the latter. The cold contact 3| is carried by an angular piece of sheet metal 3| insulatedly supported from the bracket 29. The block I 8 also supports a bracket 33 which, as more clearly shown in Figure l, supports two bushings 34 and 35. The bushing 34 is insulated as indicated and connected through a strap 36 with the bracket 3 l The bushing is grounded to the bracket 33. The bushings 34 and 35 are adapted to receive pins 3'! and 38 which are secured to heat resisting insulators 39 and 40 by bolts 4| and 42. A resistance coil 43 is secured to these bolts so that when the switch blade 30 is in engagement with the cold contact 3|, the ignition coil 43 is energized.

When the device is cold the ignition coil is in circuit so that as soon as the main valve is shifted to open the gas passages to supply gas to the pilot burner, current flows through the ignition coil 43 which is opposite ignition ports 44 in the pilot burner '21 thereby igniting the gas both as the ignition ports 44 and the pilot port 22. The flames produced at the ignition ports a l are preferably small bead-like fiameswhichheat the inside of the bent portion of ahorse-shoe or 'U-shaped thermal element 45. This thermal element may conveniently be made in the form of a heatiresistan't metal tube with relatively "thin wall (Figure 4) and it has the center of the bend close to the pilot burner 2 I. Ambient temperature changes do not change adjustments.

The free end 46 of the thermal element '45 carries an adjustable element 4! which isiin contact with the contact "spring -33 when the parts "are cold and holds the cold contact closed.

The heating of the inside of the bent portion of the thermal element45 causes .it to expand rapidly. The temperature of theremain'der or 'thetubular e'lement45 is substantially unafiected "as it hasaheat radiating capacity much greater than the .rate of heat supplied from the small Thereupon the free end 46 of the th'ermal-element is shifted to the right :as 'viewed in Figure 1. This allows the contact spring 30 to move to and engage the hot contact ili. 'This movement first opens the ignition coil circuit but as'ignition has already occurred flame propagation in the pilot burner continues. Thec'ircu'it is then established from the contact spring 30 to the hot contact 32 and then through-abracket '48 through a wire 49 leading to the solenoid so that't'he solenoid gas valve 'isopened to. supply .fuel to the 'main burner.

Where it is desired to use the present safety controlfor fuel burners in connection with an -oven .controLthe wiring leading to the solenoid may include a time clock 5| adapted to close a circuit:at adesignated time and reopen it at a later designated time, and a thermostatic regulator 152. With this arrangement it ispossible to'set'the clock for the time for the oven to be .on:emd off, set the oven temperature regulator for the desired oven temperature, and turn on the'ga's by'the main valve, whereupon the pilotiis automatically lighted and the ignition circnit'isturned :ofi'. Full control of the oven "temperature and timing is then secured without 'iurther attention.

in-Figure 6 the "owner of a gas fired furnace 'or boiler is shown-at 58. Flow of gas to it is under the'control of a solenoid valve 6 l. A small solenoid valve shows that the pilot controls have operated. This light may be remotely placed if desired.

If atany time for any reason the pilot should be extinguished, the heat energy in the tubular thermal element 45 will be quickly dissipated and it will shift the change-over switch to open the solenoid circuit to extinguish the main burner and close the ignition circuit to reignite the pilot flame so that proper operating-conditions will be .re-esta'blished. Should the vignition coil burn out or 'fail'for anyreason, itis possible to light the pilot :by a match .or'taper, whereupon the device operates except 'fior automatically re-lighting just as though it .had: been lighted automatically.

The ignition devices and thermal element are preferably placed somewhat below the main burner so as not to be in the main flamezone. While they will-receive some radiant heat from the burner and gradually heat up while the :main burner is in operation, such heating causes no functional change in the operation of the control device except for the expansion. of the :parts which may require a somewhat longer time after extinguishment of the main flame before closing of the solenoid valve. In as much as the :pilot control can be placed remote from the burner.

it is possible to mount these controls in any convenient place in the stove orfurnace "and employ a pilotitube with'suitable portsso that the dame initiated at theignition device can be propagated all the way tothe pilot port.

Since it is obvious" that the invention may be embodied in other forms and constructions within the scope of the claims, I wish it to be understood that the particular form shown is butone of these forms, and various modifications and changesbeing possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

l. A gas pilot operated circuit controller, comprising a support, a pilot burner tube having ignition flame ports and a pilot port in flame propagating relation with the .ignition flame ports, the pilot tube being fixedly carried by the support, a U-shaped thin-walled tube made-of homogeneous, thermally expansible heat-resistant metal sothat its shape does not change substantially with change of ambient temperature, the U-tubebeing secured at one end to .the support and having the other end freeand having the bend of the U about the ignition flame ports, an electric switch carried by the support having two spaced relatively fixed contacts and a :movable contact adapted to be connectedto one side of a current source and biased toward one "of the fixed contacts, means carried by the free end of the U-shaped tube for holding the movable contact in engagement with the other fixed contact when the tube is at a uniform temperature throughout its length, a resistance'coil carried by the support, disposed opposite theignition flame ports and connected to the said. other fixed contact for energization therethrough, the concave part of the bent U-shaped. tube being closely adjacent the ignition flame ports so that flame may impinge thereon and heat it to a substantially higher temperature than the outer part of the bent U-shaped tube and cause the fiexure of the bent U-shaped tube to move its free end in a direction and amount to cause the biased movable contact to open the circuit to the resistance coil and establish a circuit connection with the first mentioned fixed contact.

2. A controller as claimed in claim 1, wherein the U-shaped tube is in a horizontal plane and the pilot tube extends upwardly from the support past the U-shaped tube.

3. In combination, a gas pilot operated circuit controller in the form of a preassembled unit and comprising a support, a pilot burner tube having ignition flame ports and a pilot port in flame propagating relation with the ignition flame ports, the pilot tube being fixedly carried by the support, a U-shaped thin-walled tube made of homogeneous, thermally expansible heatresistant metal so that its shape does not change substantially with change of ambient temperature, the U-tube being secured at one end to the support and having the other end free and having the bend of the U about the ignition flame ports, an electric switch carried by the support having two spaced relatively fixed contacts and a movable contact adapted to be connected to one side of a current source and biased toward one or" the fixed contacts, means carried by the free end of the U-shaped tube for holding the movable contact in engagement with the other fixed contact when the tube is at a uniform temperature throughout its length, and a resistance coil carried by the support, disposed opposite the ignition flame ports and connected to the said other fixed contact for energization therethrough, the concave part of the bent U-shaped tube being closely adjacent the ignition flame ports so that flame may impinge thereon and heat it to a substantially higher temperature than the outer part of the bent U-shaped tube and cause the fiexure of the bent U-shaped tube to move its free end in a direction and amount to cause the biased movable contact to open the circuit to the resistance coil and establish a circuit connection with the first mentioned fixed contact, an upwardly burning main burner above the circuit controller so as to direct its flame above the controller, the main burner being in flame propagating relation with the pilot port of the pilot tube, and a normally closed, solenoid operated valve for controlling flow of gas to the main burner and electrically connected with said first mentioned fixed contact.

4. The combination of claim 3 having a variable opening main valve for controlling gas supply to the solenoid valve and to the pilot burner, and a switch operable by the main valve for energizing the circuit controller when the main valve is open.

5. A gas pilot operated circuit controller comprising a support, a U-shaped tube composed of homogeneous thermally expansible, heat-resistant metal so that its shape does not change substantially with change in ambient temperature, the U-tube being secured at one end to the support and having the other end free, a pilot burner carried by the support and having ignition flame ports within the U and a pilot port in flame propagating relation with the ignition flame ports, an electric switch carried by the support having two spaced relatively fixed contacts and a movable contact adapted to be connected to one side of a current source and biased toward one of the fixed contacts, means carried by the free end of the U-shaped tube for holding the movable contact in engagement with the other fixed contact when the tube is at a uniform temperature throughout its length, a resistance coil carried by the support, disposed opposite the ignition flame ports and connected to the said other fixed contact for energization therethrough, the concave part of the bent U-shaped tube being closely adjacent the ignition flame ports so that flame may impinge thereon and heat it to a substantially higher temperature than the outer part of the bent U-shaped tube and cause the fiexure of the bent U-shaped tube to move its free end in a direction and amount to cause the biased movable contact to open the circuit to the resistance coil and establish a circuit connection with the first mentioned fixed contact.

HERBERT J. LONG.

' REFERENCES CITED The following references are of record in the flle of this patent:

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